Democratic U.S. Senate candidate Rep. Bruce Braley (D-IA) (C) and Sen. Tom Harkin (D-IA) (L) thank volunteers before they set off to canvass the surrounding neighborhood November 3, 2014 in Iowa City, Iowa. According to the polls, Braley is in a neck-and-neck race with his opponent, Republican Joni Ernst, and the election in Iowa could decide which party controls the U.S. Senate.

Democratic U.S. Senate candidate Rep. Bruce Braley (D-IA) (C) and Sen. Tom Harkin (D-IA) (L) thank volunteers before they set off to canvass the surrounding neighborhood November 3, 2014 in Iowa City, Iowa. According to the polls, Braley is in a neck-and-neck race with his opponent, Republican Joni Ernst, and the election in Iowa could decide which party controls the U.S. Senate.

Midterms Elections Held Across The U.S.

Steve Pope

Democratic Senate Candidate Bruce Braley, left, and U.S. Senator Tom Harkin (D-IA) unite during a last minute pitch to get out the vote on the Campus of Iowa State Univeristy November 4, 2014 in Ames, Iowa. Democratic Senate Candidate Bruce Braley is in a tight race against Republican Senate Candidate Joni Ernst to fill the seat held by Harkin since 1985.

Democratic Senate Candidate Bruce Braley, left, and U.S. Senator Tom Harkin (D-IA) unite during a last minute pitch to get out the vote on the Campus of Iowa State Univeristy November 4, 2014 in Ames, Iowa. Democratic Senate Candidate Bruce Braley is in a tight race against Republican Senate Candidate Joni Ernst to fill the seat held by Harkin since 1985.

Democratic U.S. Senate candidate Rep. Bruce Braley (D-IA) (L) hugs volunteer Pat Halferty during a campaign stop at the Lynn Count Democratic Headquarters November 3, 2014 in Cedar Rapids, Iowa. According to the polls, Braley is in a neck-and-neck race with his opponent, Republican Joni Ernst, and the election in Iowa could decide which party controls the U.S. Senate.

Democratic U.S. Senate candidate Rep. Bruce Braley (D-IA) (L) hugs volunteer Pat Halferty during a campaign stop at the Lynn Count Democratic Headquarters November 3, 2014 in Cedar Rapids, Iowa. According to the polls, Braley is in a neck-and-neck race with his opponent, Republican Joni Ernst, and the election in Iowa could decide which party controls the U.S. Senate.

Democrat Bruce Braley Campaigns Ahead Of Senate Midterm Elections

Bloomberg

Representative Bruce Braley, the Democratic nominee for the U.S. Senate, smiles as he arrives at a campaign stop in Iowa City, Iowa, U.S., on Monday, Nov. 3, 2014. Braley and State Senator Joni Ernst, the Republican nominee, are tied at 47 percent in the Iowa Senate race, according to a Quinnipiac University poll of likely voters taken between Oct. 28 and Nov. 2. Photographer: Daniel Acker/Bloomberg via Getty Images

Representative Bruce Braley, the Democratic nominee for the U.S. Senate, smiles as he arrives at a campaign stop in Iowa City, Iowa, U.S., on Monday, Nov. 3, 2014. Braley and State Senator Joni Ernst, the Republican nominee, are tied at 47 percent in the Iowa Senate race, according to a Quinnipiac University poll of likely voters taken between Oct. 28 and Nov. 2. Photographer: Daniel Acker/Bloomberg via Getty Images

Democratic U.S. Senate candidate Rep. Bruce Braley (D-IA) thanks volunteers at the Lynn Count Democratic Headquarters November 3, 2014 in Cedar Rapids, Iowa. According to the polls, Braley is in a neck-and-neck race with his opponent, Republican Joni Ernst, and the election in Iowa could decide which party controls the U.S. Senate.

Democratic U.S. Senate candidate Rep. Bruce Braley (D-IA) thanks volunteers at the Lynn Count Democratic Headquarters November 3, 2014 in Cedar Rapids, Iowa. According to the polls, Braley is in a neck-and-neck race with his opponent, Republican Joni Ernst, and the election in Iowa could decide which party controls the U.S. Senate.

Democratic U.S. Senate candidate Rep. Bruce Braley (D-IA) talks with reporters after thanking volunteers November 3, 2014 in Iowa City, Iowa. According to the polls, Braley is in a neck-and-neck race with his opponent, Republican Joni Ernst, and the election in Iowa could decide which party controls the U.S. Senate.

Democratic U.S. Senate candidate Rep. Bruce Braley (D-IA) talks with reporters after thanking volunteers November 3, 2014 in Iowa City, Iowa. According to the polls, Braley is in a neck-and-neck race with his opponent, Republican Joni Ernst, and the election in Iowa could decide which party controls the U.S. Senate.

Democratic U.S. Senate candidate Rep. Bruce Braley (D-IA) talks with reporters after thanking volunteers November 3, 2014 in Iowa City, Iowa. According to the polls, Braley is in a neck-and-neck race with his opponent, Republican Joni Ernst, and the election in Iowa could decide which party controls the U.S. Senate.

Democratic U.S. Senate candidate Rep. Bruce Braley (D-IA) talks with reporters after thanking volunteers November 3, 2014 in Iowa City, Iowa. According to the polls, Braley is in a neck-and-neck race with his opponent, Republican Joni Ernst, and the election in Iowa could decide which party controls the U.S. Senate.

Democrat Bruce Braley Campaigns Ahead Of Senate Midterm Elections

Bloomberg

Representative Bruce Braley, the Democratic nominee for the U.S. Senate, listens during his introduction during a campaign stop in Fort Madison, Iowa, U.S., on Monday, Nov. 3, 2014. Braley and State Senator Joni Ernst, the Republican nominee, are tied at 47 percent in the Iowa Senate race, according to a Quinnipiac University poll of likely voters taken between Oct. 28 and Nov. 2. Photographer: Daniel Acker/Bloomberg via Getty Images

Representative Bruce Braley, the Democratic nominee for the U.S. Senate, listens during his introduction during a campaign stop in Fort Madison, Iowa, U.S., on Monday, Nov. 3, 2014. Braley and State Senator Joni Ernst, the Republican nominee, are tied at 47 percent in the Iowa Senate race, according to a Quinnipiac University poll of likely voters taken between Oct. 28 and Nov. 2. Photographer: Daniel Acker/Bloomberg via Getty Images